Scientists Grow a Miniature Human Brain in a Lab

The "brain in a jar" scenario, in which a mad scientist disembodies a person's brain and connects it to a simulated reality, is both a common science fiction trope and the subject of countless thought experiments. But now, a limited version of that scenario may have just become a reality, as researchers from Ohio State University claim to have grown a nearly complete miniature human brain in a lab.

The organoid is about the size of a pencil eraser, and was derived from human cells. According to the researchers, it is the most complete brain organoid ever developed.

"It not only looks like the developing brain, its diverse cell types express nearly all genes like a brain," study leader Rene Anand said in an OSU statement.

The brain was created using adult human skin cells that were converted into pluripotent stem cells. Once the cells become pluripotent, they can be programmed to become any organ in the body. It's more difficult to create a human brain, since it's much more complex than any other organ, but Anand and his colleagues used a technique in which they differentiated between cells that were intended to become neural tissue, parts of the central nervous system, or other types of tissue in the brain.

It takes approximately 15 weeks for an organoid to become a brain comparable to that of a 5-week-old fetus. Anand's model has grown for 12 weeks, and he believes that the remaining 1% of genes that are not expressed in the model may express themselves after 16-20 weeks, but there's no way to be sure.

While most people are not on the market for a brain transplant (and it would be somewhat terrifying if they were), this research could have massive implications for neuroscience research. Currently, most neurological studies use animals such as rats, but this new technology could allow for research that's both more humane and more accurate.

"Mathematical correlations and statistical methods are insufficient to in themselves identify causation. You need an experimental system –- you need a human brain," said Anand.

Anand and his colleagues envision this tiny brain becoming a model for experiments that could lead to treatments for strokes, traumatic brain injury, and even mental illnesses.

"We've struggled for a long time trying to solve complex brain disease problems that cause tremendous pain and suffering. The power of this brain model bodes very well for human health because it gives us better and more relevant options to test and develop therapeutics other than rodents," Anand said.